The present invention relates to a rotary piston internal combustion engine having a substantially circular cylindrical compression chamber and a substantially circular cylindrical working chamber, rotary pistons being arranged in the compression chamber and in the working chamber, jointly rotatable about an axis of the compression chamber and working chamber, slides being provided in the compression chamber and in the working chamber, arranged movable in radial direction to make sealing contact with the surface of the rotary piston in question, and a first exhaust aperture being provided on the periphery of the working chamber. Combustion engines on the rotary piston principle are especially advantageous, since they comprise no reciprocating pistons, so that smooth running and high speed are attainable.
The present invention pertains to a rotary piston combustion engine in which a partition is arranged separating the working chamber from the compression chamber, and oval rotary pistons being arranged in the compression chamber and working chamber, rotating, about an axis concentric with the compression chamber and working chamber. Compression and drive are achieved in that a slide movable substantially radially is in sealing contact with the surface of the rotary piston in question. The working chamber is larger than the compression chamber in proportion to the expansion ratio of the gaseous mixture.
Germany DE A 4,305,669 discloses such a rotary piston combustion engine. Here a smaller compression chamber and a larger working chamber are associated to accomplish the compression and combustion of the intake gas mixture and the expulsion of the exhaust gas. It is quite possible to operate such rotary piston combustion engines advantageously at certain speeds and under certain load conditions, and/or at certain air-fuel ratios, but a problem consists in that the volume of the working chamber is not variable according to the variation of speeds and load, or according to the variation of the air-fuel ratio. Two disadvantageous effects in particular thus occur:
At high speed or high load, at which a fat air-fuel ratio is applied, the expansion pressure of the burned gas cannot be completely utilized by the time the outlet slits open, so that energy is lost unused in the exhaust. The result is a relatively high fuel consumption and relatively high exhaust noise of such engines in that operating mode.
Secondly, it would be desirable in the low-speed or partial load range to achieve an earlier opening of the outlet slits to accelerate gas exchange and minimize losses.
Similar engines are disclosed in U.S. Pat. No. 2,091,120, Germany C 817,058, Germany C 822,312 and Germany A 1,931,522. In such engines also, inlet and outlet apertures are affected only by the rotary piston, whence again the disadvantages described above will arise.
Two further disadvantages of the known devices are that the rotation of the connecting disk comprise[s] a higher friction, as is shown in DE A 4,305,669, U.S. Pat. No. 2,091,120, DE C 817,058 and DE C 822,312, and that there is a sealing problem between slide, roller and rotary piston, especially in the case of a solution as provided in DE A 1,931,522.
Other motors of similar type are disclosed for example in DE C 387,287, DE C 404,080, DE A 1,476,672, France A 2,083,703 or Great Britain A 1,469,295.
The object of the present invention is to further develop the combustion engine initially described so as to make possible a new control for the volume of the working chamber, an improved connection control between compression chamber and working chamber, and an improved seal between slide, roller and rotary piston, to achieve optimal operation under various operating conditions.
According to the invention, this object is accomplished in that additional exhaust apertures are provided in the working chamber, closable by means of exhaust valves, which exhaust valves may be closed and opened successively by way of an adjusting means.
It is of the essence of the invention that the volume of the working chamber is associated with additional exhaust apertures and the exhaust valves. Thus according to the setting of the exhaust valves, the effective volume of the working space can be enlarged or reduced by closing or opening the additional exhaust apertures.
It is especially advantageous if the exhaust valves are in the form of rotary slides whose axes are substantially parallel to the axis of working chamber and compression chamber. In this way, actuation of the exhaust valves is possible in an especially simple manner. In particular, it is favorable if the adjusting means in turn is in the form of a rotary slide, preferably in connection with the exhaust valves by way of engaging levers. In this way, a dependable actuation of the exhaust valves is achieved. In a preferred modified embodiment of the present invention, provision is made to provide an exhaust manifold on the outer periphery of the working chamber, connecting the first exhaust aperture with the additional exhaust apertures.
It is especially advantageous if the connecting control valves are in the form of rotary slides arranged in the communicating apertures on the partition between the compression chamber and the working chamber, their axes substantially radial to the axis of working chamber and compression chamber. In this way, an actuation of the communicating control valves is possible with especial ease. In particular, it is favorable if the engaging grooves, preferably in communication with the connection control valves by way of engagers, are provided on the rotary pistons. In this way, a dependable actuation of the connecting control valves is achieved, the connecting control valves being rotatable by the rotary pistons in two opposed directions, and thereby opened or closed.
To especial advantage, the two slides bear rollers at the peak, sealed by sliding parts and leaf springs. In this way, the seal between slide, roller and rotary piston can be improved. The slides are guided on either side by tracks arranged on the partition and the supporting disks, which is especially important, since during the working stroke, comparatively high forces of expansion of the burned gages act one-sidedly on the slides. Wear is minimized in this way.